Excimer laser annealing (ELA) is a technique that can be used to convert a thin film of amorphous silicon (“a-Si”) into a polycrystalline silicon (polysilicon) film, for example, having a grain size of about 308 nm, without heating the underlying substrate. During ELA, a pulsed excimer laser beam is scanned across an amorphous silico surface, causing it to melt and then crystallize during cooling. A drawback of ELA-generated films is that they include high densities of surface protrusions. Other polycrystalline films can also include high densities of surface protrusions. These protrusions can have undesirable effects on the performance of electronic devices such as thin film transistors (TFTs), in which such films can be used. Given increasing needs to fabricate higher performance TFTs for future products, such as advanced active-matrix organic light-emitting diode (AMOLED) displays, a method of efficiently and uniformly planarizing polycrystalline thin films are therefore desirable.